Safety-tread unit



Mmh 1 "1927.

E, VAN DER PYL SAFETY TREAD UNIT Filed April 5. 1923 vStfa/61rd Van lder` fj/l @ifm l COMPANY, F WORCESTER, MASSACHUSETTS, A

SETTS.

EDWARD VAN DER PYL, 0F WORCESTER, MASSACHUSETTS, ASSIGNOR TO NORTON CORPORATION 0F MASSACHU- sArnTY-TREAD UNIT.

Application led April 5,

My invention relates to safety treads and more particularly to a tread unit comprlsing anti-slipping tiles.

It is found that tread blocks made of ceramic bonded abrasive material are particularly well adapted for use as safety stair treads and for floorings where the wear conditions are severe. Owing, however, to the stone-like nature of such vetrified articles,

l0 it has been found difficult to fasten these to some types of flooring. This is particularly the case where a flooring has an irre ular surface and the tiles do not rest evenly t ereon but become broken or cracked and l5 loosened from their foundation.

It is accordingly an object of my invention provide a tread unit comprising abrasive tiles fastened to a backing which may be laid on an uneven surface and will form a plane,

2o unbroken safety tread surface.

It Ais a further object to provide an article of manufacture which may be quickly and easily attached toa worn out iiooring, such as a stair, for the purpose of repairing it `and making it safe for pedestrains, and

which is general-ly serviceable as a safety tread.' Further objects will be apparent in the .following disclosure.

Referring to the drawings, illustrating embodiments of my invention, in which like reference numerals indicate like parts:

Figure 1 is a fragmentary isometric v1ew of a stair having my tread units applied thereon;

Fig. 2 is an isometric view partly broken away of one of the tread units;

Fig. 3 shows in an isometric view the application of a tread unit to a flooring; and

Fig. 4 is a sectional detail, showing one means of fastening the unit to a foundation.

In accordance with my invention, I propose toemploy blocks of bonded abrasive grains, in whichv the abrasive consists of an abrasive material, such as crystalline alumina 5 or silicon carbide, or other substance pref- 1923. Serial No. 630,102.

Dodge, No. 1,377,960 and Beecher No. 1,377,957 of May 10, 1921.

As illustrated, tiles 1 of ceramic bonded abrasive grains, which may be of small size and therefore convenient to handle and to assemble on -a rough surface, may be mounted on a backing 2 of deformable material, which is capable of holding the blocks in place. This backing preferably consists of a medium which is not brittle or rigid but can flow slightly or deform sufliciently to fit the uneven contour of a substantially plane surface and thereby make a firm contact therewith, so that the tiles may be supported on a dead foundation through which shocks and vibrations are not easily transmitted. This material must have the further capability of firmly adhering to the tiles and withstanding the ordinary climatic conditions, so that the tiles may be held in place when exposed to normal summer temperatures or rain and ice. As a suitable backing material for the tiles, I may employ a resinous, bituminous or asphaltic material, such as Trinidad asphalt combined with such substances as powdered limestone capable of strengthening or hardening the plastic asphalt and making it more resistant to heat. However, various other substitutes, both natural and synthetic, may be employed, provided they will satisfactorily serve as a deformable backing material which will readily adhere to the t1le Surface, such as by permeating the surface pores' thereof, and is capable of .holding the tiles firmly in a desired position on an uneven surface.

As shown particularly in Fig. 2, my preferred arrangement involves spacing the tiles from one another and partially embedding them in and supporting them on the plastic backing in a tessellated formation, so that the backing contacts not only with the bottoms of the tiles but with their sides as well. The crevices 3 between the tiles are filled substantially flush with the tile A tread surfaces. Since the plastic tarry material is hi hly deformable and incapable of maintaining the tread faces in a plane, 1 place reinforcement in the backing, and preferably use a heavy woven wire screen 4 of open mesh through which a nail may be driven. Consequently while the comparatively thick backing 2 may flow or deform to fit a surface beneath, the tiles above are maintained in position by the reinforcement screen. The reinforcement is -preferably open meshed or made of spaced portions so that the backing may flow through it while the tread is being manufactured. It is clear that various constructions may be employed 'for this open meslied reinforcement- As shown, the nosiiig tiles may be'longer than the others so as to be conspicuous and be capable of clearly defining the stair edge.

As a simple method of manufacturing this unit, I may place the blocksface down in a suitable mold and then pour the semi-soft bituminous backing upon the blocks with the reinforcing screen properly positioned therein, after which the mass may be subjected to pressure to force the backing material into close Contact with the blocks and between their side faces.

Owing to the use of a relatively soft, deformable backing, this tread unit is particularly adapted for surfaces which are not plane and smooth, and may be employed particularly in the repair of wooden stairways without necessitating removing the old treads. As illustrated in Fig. 1 of the drawings, which shows portions of two steps with tread units mounted thereon, this tread unitmay be fastened to the stair by suitable means such as long slender nails 6, shown on the upper step. These nails are driven through the relatively soft filling material between the tiles and the backing and into the wood beneath.

In order to doubly secure the tread unit on the stair, I may employ a metal strip so fastened as to prevent the tread unit slipping forward on its base. This metal strip may comprise a fiat piece of metal folded on -itself into a substantially T-shapied form. This strip which is nailed or screwed to the front of the stair is so proportioned and shaped that one arm 7 of the T-projects upwardly but not as high as the top of the nosing tile, so that the full benefit may be derived from the abrasive nosing and a pedestrians footgear will not Contact with the metal strip when it rocks about the nosing of the stair. The other arm 8 of the T, whichl 1s preferably the folded portion, pro- ]ects downwardly against the front edge of the wooden stair board. The body 9 of the T projects beneath the nosing tile and is fastened to the upper side of the tread board by nails or the like. While I may in certain instances employ an ordinary L-sliaped brass strip, the T-forni is preferable on old stairs.

If the tread board has become badly worn, I preferably level up its surface so as to support the tread units more firmly and thereby prevent warping of the comparatively soft backing. This may be accomplished by using a suitable cementitious material, such as a composition similar to that of the tread unit backing or Portland cement or magnesium oxychloride cement. This material 10 is trowelled in plastic condition on the board and the metal T-rail is secured in place before the cement has hardened. If the cement should become loosened or broken, it is held in place by the rail and cannot escape and leave thel tread unit unsupported on the nose where the support should be most firm. If an iron stairway is being repaired and it is desirable to use a cement thereon, I may employ' any oneV of the well known preparations on the market, such as iron cement comprising iron filings and a bond of salaminoniac.

In case it is notfeasible or desirable to drive nails through the backing, I may fasten the tread unit to the stair by screws or bolts inserted through a tile or the spacing material between the tiles. As illustrated in F ig. 4, and on the lower ste of Fig. 1, certain of the tiles may have per orations 12 therethrough and a perforated meta-l strip 14 located in or beneath the tile so that a bolt or screw 15 may be inserted through the tread unit into the foundation beneath. The space above the bolt head may be afterwards filled with cement flush with the tread surface. If the unit is applied to an iron stair this form is obviously preferable.

In many instances it is desirable to lay a safety tread flooring in certain limited localities, such as in front of a machine tool where the operator stands. As illust-rated in Fig. 3, one may cut away a part of the flooring and lay the tread units with their upper surfaces 'in the same plane as the remainder of the floor. If the cut away space is deeper than the tread unit thickness, it may be partly filled with plastic material as shown in Fig. .3, or other methods may be employed to insure having thetile surface level with the remainder of the-floor.

It will therefore be seen that a tread unit may, in accordance with this invention, be

ylaid on a rough surface and pressed or tamped in position to cause the backing material to flow into firm contact with the uneven under surface, but the tiles themselves will remain in position if the installation is properly made. These units may be applied to a flooring the same as a wooden board merely by nailing them in position. These tread units may be combined with other types of flooring, such as boards or smooth tiles, the latter being of course placed distant from the stairvnosing and where the trafic wear is not severe. Various modifications of this invention will be obvious andv it is intended that such shall be covered by my invention within the scope of the claims appended hereto.

I claim: i 1. A safety tread unit comprising antislipping tiles of bonded abrasive grains parv tially imbedded in a plastic and deformable backing material which is not meltable under ordinary climatic conditions and is capable of adhering to and supporting the tiles and yet adapted to conform to slight irregularities in a substantially plane supporting surface and make a. firm contact therewith so that the tiles may be supported on a good foundation through which shocks and vibrations are not easily transmitted and an open meshed reinforcement embedded in said backing and adapted to position and maintain the tread faces substantially in one plane.

2. A safety7 tread unit comprising antislipping tiles of bonded abrasive grains partially` imbedded in a plastic deformable backing material capable of adhering to and supportin the tiles and yet adapted to conform to sight irregularities in a substantially plane supporting surface and make a firm contact therewith so that the tiles may be supported on a good foundation through which shocks and vibrations are not easily transmitted, and an open meshed reinforcement imbedded in said backing and adapted to position and maintain the tread faces substantially in one plane. said tiles being so spaced and located that fasteners may pass through said backing between the tiles and through the reinforcement to fasten them to a foundation Signed at Worcester, Massachusetts, this 29th day of March, 1923.

EDWARD VAN DER PYL 

